ORGANIC MATTER. 11 



the atoms. In the amylaceous and saccharine group of com- 

 pounds, solidity is the habitual state : such of them as can 

 assume a liquid form, doing so only when heated to 300^ or 

 400° F. ; and decomposing when further heated, rather than 

 become gaseous. Resins and gums exhibit general physical 

 properties of like character and meaning. 



In chemical stability these ternary compounds, considered 

 as a group, are in a marked degree below the binary ones. 

 The various sugars and kindred bodies, decompose at no very 

 high temperatures. The oils and fats are also readily carbon- 

 ized by heat. Resinous and gummy substances are easily 

 made to render up some of their constituents. And the 

 alcohols with their allies, have no great power of resisting 

 decomposition. These bodies, formed by the union of 



oxygen, hydrogen, and carbon, are also, as a class, chemically 

 inactive. The formic and acetic are doubtless energetic 

 acids ; but the higher members of the fatty -acid series are 

 easily separated from the bases with which they combine. 

 Saccharic acid, too, is an acid of considerable power ; and 

 sundry of the vegetal acids possess a certain activity, 

 though an activity far less than that of the mineral acids. 

 But throughout the rest of the group, there is shown but a 

 small tendency to combine with other bodies ; and such com- 

 binations as are formed have usually little permanence. 



The phenomena of isomerism and polymerism. are of fre- 

 quent occurrence in these ternary compounds. Starch and 

 dextrine are isomeric. Fruit sugar, starch sugar, eucalyn, 

 sorbin, and inosite, are polymeric. Sundry of the vegetal 

 acids exhibit similar modifications. And among the resins 

 and gums, with their derivatives, molecular re-arrangements 

 of this kind are not uncommon. 



One further fact respecting these compounds of carbon, 

 oxygen and hydrogen, should be mentioned ; namely, that 

 they are divisible into two classes — the one consisting of sub- 

 stances that result from the destructive decomposition of 

 organic matter, and the other consisting of substances that 



